JPH05305409A - Method for forming metal - Google Patents

Abstract

PURPOSE:To form a product having excellent strength in the high dimensional accuracy even in the case of having a complicated shape by press-forming a primary product formed with a die casting process into the size and the shape of a finish product in a half-melting state having a specified solid phase ratio. CONSTITUTION:The primary product A executing the die casting in taken out from a die casting machine and the primary product A is press-formed into the shape and size as the finish product B in the following pressing process. In the pressing process, the primary product A produced by die casting is returned back to the half-melting state having 30-70% the solid phase ratio and in this condition, this product is press-formed with a pressing die. That is, the primary product A is incorporated into a holder-die 1 for heating having an inner part shape being suitable to the profile of the primary product A and heated until the primary product A becomes half-melting state having 30-70% solid phase ratio in the holder die 1 for heating, and this half-melting product is press-formed with the pressing die in a pressing machine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal forming method, and more particularly to a metal forming method for forming a product having a desired shape from molten metal.

[0002]

2. Description of the Related Art A metal forming method for forming a desired shape product from molten metal includes a gravity casting method in which a molten metal is poured into a mold such as a sand mold or a mold, and the molten metal is molded in a mold cavity. Die casting method that injects into the mold, squeeze casting method that applies high pressure to the molten metal in the mold cavity to mold and solidify it (molten forging method), or thixocast that press-molds a semi-molten metal into the mold cavity. There is a law.

[0003]

The present invention is different from these conventional metal forming methods even in products having complicated shapes,
It is intended to provide a novel metal forming method capable of forming a defect-free sound product having excellent strength with high dimensional accuracy.

[0004]

[MEANS FOR SOLVING THE PROBLEMS] The metal forming method of the present invention which achieves such an object is a die casting step of forming a primary processed product having a shape close to the final product shape by die casting, and a solid-phase ratio of the primary processed product. It is characterized by comprising a pressing step of press-forming into a size and shape of a final product in a semi-molten state of 30 to 70%, and in the die casting step, the solid phase ratio of the molten metal in the injection sleeve is 0 to 50%. In that state, the cavity is filled at high speed, and further, the primary processed product is put into a heating holder mold having an internal shape suitable for the profile of the primary processed product and heated to a semi-molten state. It was done.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The metal forming method according to the present invention basically comprises a die casting step of forming a primary processed product A close to the final product shape by die casting, and a solid-phase ratio of the primary processed product A cast-molded in the die casting process to 30 to 70. %, In the semi-molten state, and press-molded into the size and shape of the final product B.

In the die casting process, a primary processed product A having a shape close to the shape and size of the final product of the desired product is formed by the die casting method. In the die casting process according to the present invention, various known die casting methods can be adopted,
Above all, it is preferable to cast and form the primary processed product A by the non-porous die casting method (PF die casting method).

When die-casting the primary processed product A, the pouring temperature is set to a low temperature, and the cavity is filled at high speed with the solid fraction of the molten metal in the injection sleeve set to 0 to 50%. Preferably. This is because when the solid fraction of the molten metal in the injection sleeve is 50% or more, the fluidity of the molten metal during injection becomes extremely poor and various defects are likely to occur in the primary processed product A. The high-speed filling of the molten metal causes the dendrite crystals grown in the melt to be destroyed by the high-speed filling to form a fine crystal structure, which makes it possible to make the crystal structure of the primary processed product A into a fine spherical shape, and as a result, in the next pressing step. This is because the metal fluidity is improved when the primary processed product A is press-molded.

In this way, the die-cast cast primary processed product A is taken out from the die casting machine, and the primary processed product A is press-formed into the final product B in the shape and size in the next pressing step.

In the pressing step, the die cast primary processed product A is returned to a semi-molten state with a solid fraction of 30 to 70%,
In that state, press molding is performed with a press die. That is, the primary processed product A cast in the die casting process is housed in the heating holder mold 1 having an internal shape that matches the profile (external shape) of the primary processed product A, and the primary processed product A is placed in the heating holder mold 1. The processed product A is heated to a semi-molten state with a solid phase ratio of 30 to 70%, and the semi-melted processed product C is press-molded by the press die 3 of the press machine 2.

When the primary processed product A is press-molded in a semi-molten state, if the solid phase ratio of the primary processed product A is 70% or more,
The fluidity of the metal deteriorates significantly, and the solid fraction is 3
If it is 0% or less, the self-supporting property as a processed product is lost, and it becomes difficult to set the press mold 3.

As shown in FIG. 1, the heating holder die 1 for heating the primary processed product A comprises two split molds 1a and 1b having an internal shape adapted to the profile (external shape) of the primary processed product A. Composed of. And the split type 1a, 1b is
Outer frame 11 made of a heat-resistant material having heat insulation properties and formed in a substantially box shape 11
And a heater 12 and a metal holder 13 housed and installed inside the metal holder 13. The outer surface 13a on one side of the metal holder 13 is adapted to the profile (external shape) of the primary processed product A, and A cushion material 14 made of asbestos is attached to the outer surface 13a on one side of the holder 13 as needed.

Thus, when the die-cast casting primary processed product A is accommodated in the heating holder mold 1, the interior of the heating holder mold 1 is removed immediately after removing the casting burrs of the primary processed product A taken out from the die casting machine. Or receive it directly with one split mold (for example split mold 1a) of the holder mold 1 for heating without removing burrs, and wrap it with the other split mold (for example split mold 1b) for storage. The temperature of the primary processed product A is prevented from decreasing.

In the pressing step, the surface of the press die 3 is coated with a powdery heat insulating agent, or the surface of the primary processed product A, that is, the surface A'on the side where the press die 2 is set, is appropriately used. It is desirable to prevent a decrease in temperature due to heat conduction when the semi-molten processed product C is set in the press die 3 by, for example, projecting a protrusion having a height. Then, the rapid solidification action in the pressing process can be embodied remarkably.

Further, when the semi-melt processed product C is set in the press die 3 of the press 2, the semi-melt processed product C is not completely taken out from the heating holder mold 1, but as shown in FIG. If the mold 1 is set and held in one of the split molds (for example, the split mold 1a) and set in the press mold 3, it is safe to handle, and the semi-melt processed product C is prevented from being deformed and pressed quickly. It becomes possible to shift to the process.

Alternatively, a protrusion may be formed in advance in the same body on a part of the primary processed product A, and the protrusion may be pushed toward the product in the pressing step. That is,
When the primary processed product A is cast-molded in the die-casting process, a protrusion irrelevant to the product shape is formed on a part of the primary processed product A so as to project, and the protrusion is pressed by the pressing machine 2 in the pressing process. The mold 3 may be pressed into the inside of the product so as to be crushed in the same plane as the surface of the final product B.

[0016]

According to the metal forming method of the first aspect of the present invention, the following operational effects are exhibited. Using any die-castable aluminum alloy, zinc, magnesium alloy, etc., products with complicated shapes can be easily formed. When die-casting the primary processed product, there is no fear that the product will be adversely affected even if it is molded to some extent rough. That is, when die-casting the primary processed product, even if seizure or molten metal flow failure, or cracks caused by die-casting of non-cast alloy occur, the primary processed product is press-formed in a semi-molten state. As a final product, these adverse effects can be corrected by a pressing process, and as a result, a sound and defect-free product can be finally molded. Since the final product shape / dimension (primary processed product) is press-molded in the semi-molten state, the flow length by the press is shortened, and defects such as filling failure may occur as in the thixocast method. It is possible to mold a sounder product. Since the die-casted primary processed product is pressed into a semi-molten state and press-formed, defects such as pinholes hardly occur due to the high pressure and rapid solidification action of the press die, and the dendrite arm spacing of the primary processed product is reduced. The fluidity is improved, and the pressing pressure in the pressing process is effectively effective until the solidification is completed, and as a result, a product having a high density and excellent mechanical properties can be molded.

According to the second aspect of the metal forming method of the present invention, in addition to the first aspect, the following operational effects are exhibited. Since the melt temperature can be set low when die-casting the primary processed product, it is possible to minimize the influence of variations in the molten metal temperature and suppress the growth of dendrites. Can be made finer. In addition, by filling the molten metal into the cavity at high speed, it becomes possible to make the crystal structure of the primary processed product into a finer sphere like the billet in the thixocasting method.
As a result, when the primary processed product is press-molded in a semi-molten state, the metal fluidity is improved, and a more sound and excellent product can be molded.

Furthermore, according to the metal forming method of the third aspect of the present invention, in addition to the first aspect, the following operational effects are exhibited. Since it becomes easy to uniformly heat the primary processed product uniformly, and therefore the solid phase of the primary processed product can be made uniform, the flow of the semi-molten metal in the press forming in the pressing step becomes good. Since it is not necessary to heat the primary processed product from room temperature, it is possible to shorten the heating time of the primary processed product and save energy. When the primary processed product is heated to the semi-molten state and when the semi-melt processed product is set in the press die, it becomes easy to hold the semi-melt processed product without deforming, and the moldability of the semi-melt processed product is improved. Easy to hold.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a heating holder type according to the present invention.

FIG. 2 is a cross-sectional view showing a state in which a primary processed product is set in a press die of a press machine.

FIG. 3 is a cross-sectional view showing a state in which a primary processed product is pressed by a press die of a press machine.

FIG. 4 is a cross-sectional view showing a state where a primary processed product is pressed by a press die of a press machine.

[Explanation of symbols]

 A: Primary processed product B: Final product C: Semi-melt processed product 1: Heating holder type 2: Press machine 3: Press type

Claims (3)

[Claims] 1. A die-casting step of forming a primary processed product having a shape close to that of the final product by die casting, and pressing the primary processed product into the size and shape of the final product in a semi-molten state with a solid fraction of 30 to 70%. A metal forming method comprising a forming step and a forming step. 2. The metal forming method according to claim 1, wherein in the die casting step, the molten metal in the injection sleeve is filled in the cavity at a high rate with the solid fraction of the molten metal being 0 to 50%. 3. The metal forming method according to claim 1, wherein the primary processed product is placed in a heating holder mold having an internal shape adapted to the profile of the primary processed product and heated to a semi-molten state. ..